A lighting apparatus such as a flashlight or electric lantern typically serves a number of purposes. For example, it may be used to illuminate a nearby extended area or a distant object. A flashlight adapted for illuminating distant objects preferably has a narrowly focused spot beam. A flashlight designed for viewing a nearby extended area should have a broad flood beam.
Known flashlights typically generate only a spot beam for illuminating distant objects. No provision is usually made for generating a separate flood beam. Those flashlights that do provide both a spot beam and a flood beam often do so in inconveniently controlled, or complex ways. For example, mechanically separate attachments have been provided for diffusing the light from the spot beam. Such attachments, however, are bulky and require time to couple them to the flashlight. Other devices use separate lighting sources for each beam, but these tend to be too large to offer the versatility and ease of use of a hand-held flashlight. Still other devices use mechanical linkages to move the light source out of the focal point of the collimator. Such devices, however, provide uneven flood beams with gaps in the center of the beam.
It is also desirable for a flashlight to provide light in different colors. For example, in order to preserve night vision, an individual working in a darkened environment usually prefers to illuminate a nearby object with red light. However, to examine an object in more detail and at the risk of losing night vision, it may be preferable to illuminate the object with white light. Thus, a single lighting apparatus providing both red light and white light would be advantageous. However, known lighting devices that provide more than one color of light typically require more than one light source or filters that must be changed, or use clumsy mechanical actuations.
The present invention overcomes these well documented deficiencies of prior art devices by providing lighting devices in which characteristics of the emitted light such as its direction, divergence and color can be switchably controlled in an extremely simple, reliable, compact, convenient and efficient manner.